For those lucky enough to live in the world's wealthier nations, tuberculosis is an illness with an old-fashioned ring. The Victorians called it consumption, a wasting disease that was no respecter of class, responsible for one out of every four deaths in early 19th-century Britain. It probably carried off some of our greatest talents, from Emily Bronte to John Keats and DH Lawrence - and more recently Vivien Leigh. Its shadow has faded now, though TB is increasing again even here; 7,000 cases a year in Britain, half of them in London. Even so, thanks to antibiotics and mass immunisation, the hundreds of TB sanatoria that once dotted Europe are now historical curiosities.
However in much of the rest of the world, especially Asia and Africa, TB remains a much deadlier threat. That is why yesterday - March 24 - was designated "world TB day": both to commemorate the day in 1882 when German bacteriologist Robert Koch first identified the tuberculosis bacillus and as an unhappy reminder that the infection is still at large - with devastating effect.
Along with malaria and HIV/Aids, TB makes up the trinity of killers that are the most common deadly infectious diseases worldwide. The statistics are staggering: some 2 million die from TB each year. Were it not for HIV/Aids, TB would still be the world's most dangerous disease. Yet TB has received a grotesque boost from the spread of HIV/Aids, to form a deadly double act. Because of the ravages of their immune systems, around a third of all HIV sufferers also develop TB, and an estimated 14 million people worldwide are co-infected with TB and HIV.
While south-east Asia and the former Soviet Union suffer greatly from TB, it is the people of Africa who are the worst hit, thanks to the prevalence of HIV and the weakness of public health infrastructure. Despite the efforts of the World Health Organisation and many others, the struggle against TB remains hard. That is why the recommendations of the Africa Commission must not be overlooked. Its report warned that many African countries' health care systems are in danger of disintegrating "beyond repair". Health spending per head in Africa is just $13-$21 a year, compared with more than $2,000 per head in the developed world. If ever there was a problem that could be solved by throwing money at it - enough to raise per person spending to $38 a year - this is one. The additional $50bn a year, for 10 years, called for by the commission, must be contributed by the world's wealthy, so that one day March 24 can be remembered for its historical significance alone.
